How to check if a collider overlaps with sphere?

I have a list of colliders I need to check against.

I don't want to use any of the Physics methods because those check against every colliders and it would be too expensive.

How can I know if Collider A overlaps with a sphere B of a certain radius?

 

What kind of collider is A? If they're both spheres it's as simple as checking if the distance between their centers is less than the sum of the two spheres radii.

You can also use layer masks to optimize Physics.Overlap operations.

 

What would be best is that it worked with any of the Collider's base class aka with spheres, box, capsules, terrain collider, mesh colliders.

Is there no way provided by Unity to check if a collider overlaps a sphere?

 

There is but they're all contained in the dreaded Physics class that you are avoiding.

The other options are to use the collider callbacks such as OnTriggerEnter etc..

 

I understand that problems can usually be tackled with OnTriggerEnter however I'm in a specific situation.

I have already discovered colliders with OnTriggerEnter in a certain area around my particle system.

And now, I want to discover if a particle overlaps one of the colliders found in OnTriggerEnter.

I'm trying to have particles detect triggers, you can see more about that in this thread: https://forum.unity.com/threads/par...ecting-particle-velocity.881008/#post-5792485

The problem is that OnParticleTrigger does not provide which trigger it has entered.. So I must somehow find the trigger it has collided with myself.
https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnParticleTrigger.html

 

So just to be clear, the particle is the sphere in this question?

Is the particle small enough that we could get away with just treating it as a dimensionless point instead of a sphere?

Unfortunately I don't think there's a one-size-fits-all approach that will match all collider types. How pinpoint accurate does this have to be?

 

Yes

No, the ideal would be that it's a sphere with a custom radius present in the Particle System's trigger module.
https://i.imgur.com/EYT1GV6.gifv